explain why the surface tension of water is greater than that of methylated spirit?
intermolecular Hydrogen bonding in the water.
The intermoleculer forces of water are greater than of methylated spirit
The surface tension of a liquid refers to the force that acts on the surface molecules of the liquid, causing them to behave as if they were covered by a stretched elastic film. The surface tension is determined by the cohesive forces between the molecules in the liquid.
In the case of water, its high surface tension can be attributed to two main factors: hydrogen bonding and polarity. Water molecules are polar, meaning they have a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. These polar molecules attract each other, creating strong cohesive forces. Additionally, water molecules form hydrogen bonds with neighboring water molecules, which further increases the strength of the cohesive forces. This results in a high surface tension of water.
On the other hand, methylated spirit (also known as denatured alcohol) is a mixture of alcohol and other substances like methanol or denatonium to make it unfit for consumption. Alcohol molecules, such as ethanol in methylated spirit, have weaker cohesive forces compared to water due to the absence of hydrogen bonding. This leads to a lower surface tension of methylated spirit compared to water.
To determine the surface tension of a liquid experimentally, one common method is to measure the height to which the liquid can be raised in a capillary tube. The liquid is drawn up in the tube due to the cohesive forces at the surface and the adhesive forces between the liquid and the tube. By comparing the height of different liquids in the capillary tube, you can determine their relative surface tensions.